I've found it more common at interstate gas stations than at local gas stations. E.g. the one that always does it for me is Hooksett, NH; with a Tesla Superchar

I've found it more common at interstate gas stations than at local gas stations. E.g. the one that always does it for me is Hooksett, NH; with a Tesla Supercharger, it is more a place that serves everyone and their mother than a lower income area.